sandbox -X doesn't work in F13

[anonymous]

Dear Sir or Madam,

when I run sandbox -X (e.g. sandbox -X xterm or sandbox -X -t sandbox_web_t 
firefox) nothing happens and I just silently get thrown back to the shell. 
Furthermore, I noticed that /usr/share/sandbox/sandboxX.sh when run 
individually prints "Hangup". Is this normal? What can I do to make it work? 
[I'm on a Lenovo T61 with an up-to-date Fedora 13 KDE version and installed 
policycoreutils-sandbox.]

I already tried both forum and IRC, but had no luck in finding an answer, yet. 
Thus - and since sandbox -X is imho one of the coolest features of Fedora - I 
would really appreciate suggestions to fix it.

Thank you in advance.


Best regards,
Falk